David A. Turner (26 January 1946 – 19 October 2023) was a British computer scientist. He is best known for designing and implementing three

programming language A programming language is a system of notation for writing computer programs. Programming languages are described in terms of their Syntax (programming languages), syntax (form) and semantics (computer science), semantics (meaning), usually def ...

s, including the first for

functional programming In computer science, functional programming is a programming paradigm where programs are constructed by Function application, applying and Function composition (computer science), composing Function (computer science), functions. It is a declarat ...

based on

lazy evaluation In programming language theory, lazy evaluation, or call-by-need, is an evaluation strategy which delays the evaluation of an Expression (computer science), expression until its value is needed (non-strict evaluation) and which avoids repeated eva ...

, combinator graph reduction, and polymorphic types: SASL (1972),

Kent Recursive Calculator KRC (Kent Recursive Calculator) is a lazy functional language developed by David Turner from November 1979 to October 1981 based on SASL, with pattern matching, guards and ZF expressions (now more usually called list comprehensions). Two i ...

(KRC) (1981), and the commercially supported Miranda (1985). Turner's work on Miranda had a strong influence on the later

Haskell Haskell () is a general-purpose, statically typed, purely functional programming language with type inference and lazy evaluation. Designed for teaching, research, and industrial applications, Haskell pioneered several programming language ...

. Turner first implemented SASL using the abstract SECD machine, but then reimplemented them in 1978 using

SKI combinator calculus The SKI combinator calculus is a combinatory logic system and a computational system. It can be thought of as a computer programming language, though it is not convenient for writing software. Instead, it is important in the mathematical theory o ...

. This approach was used by Thomas Johnsson and Lennart Augustsson in the design of the g-machine that evolved to become the standard mechanism for

in call-by-need languages. In 1981, Turner received the

Doctor of Philosophy A Doctor of Philosophy (PhD, DPhil; or ) is a terminal degree that usually denotes the highest level of academic achievement in a given discipline and is awarded following a course of Postgraduate education, graduate study and original resear ...

(D.Phil.) from the

University of Oxford The University of Oxford is a collegiate university, collegiate research university in Oxford, England. There is evidence of teaching as early as 1096, making it the oldest university in the English-speaking world and the List of oldest un ...

, for his dissertation "Aspects of the Implementation of Programming Languages: The Compilation of an Applicative Language to Combinatory Logic", supervised by

Christopher Strachey Christopher S. Strachey (; 16 November 1916 – 18 May 1975) was a British computer scientist. He was one of the founders of denotational semantics, and a pioneer in programming language design and computer time-sharing.F. J. Corbató, et al., T ...

and

Dana Scott Dana Stewart Scott (born October 11, 1932) is an American logician who is the emeritus Hillman University Professor of Computer Science, Philosophy, and Mathematical Logic at Carnegie Mellon University; he is now retired and lives in Berkeley, C ...

. He held professorships at Queen Mary College, London,

University of Texas at Austin The University of Texas at Austin (UT Austin, UT, or Texas) is a public university, public research university in Austin, Texas, United States. Founded in 1883, it is the flagship institution of the University of Texas System. With 53,082 stud ...

and the

University of Kent The University of Kent (formerly the University of Kent at Canterbury, abbreviated as UKC) is a Collegiate university, collegiate public university, public research university based in Kent, United Kingdom. The university was granted its roya ...

at Canterbury, where he spent most of his career and retained the title of Emeritus Professor of Computation. Turner was involved with developing

international standard An international standard is a technical standard developed by one or more international standards organizations. International standards are available for consideration and use worldwide. The most prominent such organization is the International O ...

s in programming and informatics, as a member of the

International Federation for Information Processing The International Federation for Information Processing (IFIP) is a global organisation for researchers and professionals working in the field of computing to conduct research, develop standards and promote information sharing. Established in 19 ...

(IFIP) IFIP Working Group 2.1 on Algorithmic Languages and Calculi, which specified, maintains, and supports the

ALGOL 60 ALGOL 60 (short for ''Algorithmic Language 1960'') is a member of the ALGOL family of computer programming languages. It followed on from ALGOL 58 which had introduced code blocks and the begin and end pairs for delimiting them, representing a ...

and

ALGOL 68 ALGOL 68 (short for ''Algorithmic Language 1968'') is an imperative programming language member of the ALGOL family that was conceived as a successor to the ALGOL 60 language, designed with the goal of a much wider scope of application and ...

. He was also a member of the IFIP Working Group 2.8 on Functional Programming, which related to his creation of Miranda. Turner was an emeritus professor at the

and

Middlesex University Middlesex University London (legally Middlesex University and abbreviated to MDX) is a public research university based in Hendon, northwest London, England. The university also has campuses in Dubai and Mauritius. The name of the university is ...

in England. Turner's parents were second-generation

Jewish Jews (, , ), or the Jewish people, are an ethnoreligious group and nation, originating from the Israelites of History of ancient Israel and Judah, ancient Israel and Judah. They also traditionally adhere to Judaism. Jewish ethnicity, rel ...

immigrants, and Turner himself was a strong advocate for equal rights for

Palestinians Palestinians () are an Arab ethnonational group native to the Levantine region of Palestine. *: "Palestine was part of the first wave of conquest following Muhammad's death in 632 CE; Jerusalem fell to the Caliph Umar in 638. The indigenou ...

. He was an executive member of ICAHD UK and frequently spoke on the topic. Turner died on 19 October 2023, at the age of 77.

Publications

* Turner, David A. SASL language manual. Tech. rept. CS/75/1. Department of Computational Science,

University of St Andrews The University of St Andrews (, ; abbreviated as St And in post-nominals) is a public university in St Andrews, Scotland. It is the List of oldest universities in continuous operation, oldest of the four ancient universities of Scotland and, f ...

, 1975. * * ''Another Algorithm for Bracket Abstraction'', D. A. Turner, Journal of Symbolic Logic, 44(2):267–270, 1979. * ''Functional Programming and its Applications'', D. A. Turner,

Cambridge University Press Cambridge University Press was the university press of the University of Cambridge. Granted a letters patent by King Henry VIII in 1534, it was the oldest university press in the world. Cambridge University Press merged with Cambridge Assessme ...

1982. * ''A Parser Generator for use with Miranda'', ACM Symposium on Applied Computing, pages 401–407, Philadelphia, USA, February 1996. * ''Elementary Strong Functional Programming'', D. A. Turner, in R. Plasmeijer, P. Hartel, eds, "First International Symposium on Functional Programming Languages in Education",

Lecture Notes in Computer Science ''Lecture Notes in Computer Science'' is a series of computer science books published by Springer Science+Business Media since 1973. Overview The series contains proceedings, post-proceedings, monographs, and Festschrifts. In addition, tutorials ...

, volume 1022, pages 1–13,

Springer-Verlag Springer Science+Business Media, commonly known as Springer, is a German multinational publishing company of books, e-books and peer-reviewed journals in science, humanities, technical and medical (STM) publishing. Originally founded in 1842 in ...

, 1996. * ''Ensuring Streams Flow'', Alastair Telford and David Turner, in Johnson, ed., "Algebraic Methodology and Software Technology", 6th International Conference, AMAST '97, Sydney Australia, December 1997, Lecture Notes in Computer Science, volume 1349, pages 509–523. AMAST, Springer-Verlag, December 1997. * ''Ensuring the Productivity of Infinite Structures'', A.J.Telford, D.A.Turner, "Technical Report TR 14-97", 37 pages, Computing Laboratory, University of Kent, March 1998. Under submission to "Journal of Functional Programming". * ''Ensuring Termination in ESFP'', A. J. Telford and D. A. Turner, in "15th British Colloquium in Theoretical Computer Science", page 14, Keele, April 1999. To appear in "Journal of Universal Computer Science". * ''A Hierarchy of Elementary Languages with Strong Normalisation Properties'', A.J.Telford, D.A.Turner, "Technical Report TR 2-00", 66 pages, University of Kent Computing Laboratory, January 2000. * ''Total Functional Programming'', Keynote address, pp 1–15, SBLP 2004, Rio de Janeiro, May 2004. * ''Church's Thesis and Functional Programming'', in A. Olszewski ed., "Church's Thesis after 70 years'", pages 518-544, Ontos Verlag, 2006.

References

External links

* , University of Kent at Canterbury
Staff page
at Middlesex University archived on Archive.org
Miranda functional programming language
{{DEFAULTSORT:Turner, David 1946 births 2023 deaths Academics of Queen Mary University of London Academics of the University of Kent Academics of Middlesex University British computer scientists Members of the Department of Computer Science, University of Oxford Alumni of Brasenose College, Oxford Programming language designers Programming language researchers